In known fuel injectors operated as electromagnetically actuable valves, a valve tube forming the base element of the valve is made up of three individual components. A core and a valve-seat support are interconnected in a hydraulically sealing manner via a non-magnetic intermediate component, at least two joints and connection points being required (German Patent No. DE 40 03 227, for instance).
From German Patent Application No. DE 195 03 821, a fuel injector in which the number of components of the valve tube is reduced is already known, so that the number of joints and connection points is reduced as well. The entire valve tube is made of magnetically conductive or magnetizable material, so that no non-magnetic intermediate parts are required at all. In the region of the axial extension of a magnetic armature, the one- or two-part valve tube is provided with a thin-walled magnetic restriction, so that the magnetic lines of force in the magnetic circuit are routed in an effective manner.